I am having an issue with my 99 XJR the second I turn the ignition on the car says restricted performance and the ecu is not showing any fault codes.

I know the MAF is bad as the car will not run with it plugged in but the car does not show any fault codes with the MAF unplugged.

The check engine light is always on but again no codes.

Are the engine codes stored in the ECU/ECM? and will my ECU from my 01 XJR work just to try and narrow down the problem?

 

Not likely a ECM problem, but look for the VCATS label in the trunk and see if the ECM numbers match. I doubt they will.

 

I'll take a look at the numbers and see if they match, I'm just guessing at this point at what it might be the car goes into instant restricted mode at soon as the ignition is turned on.

 

First of ALL...............AJ26 engine management WILL NOT WORK with AJ27 ECM.

1999 XJR is AJ26 and 2001 is AJ27!!!!!!!!!!!!!!!!!!

Second is the fact that the ECM will need to be configured to the CAN bus (immobilization-setup performed).

Each time an ECM is moved from the original CAN bus it must be configured to the different car. Then if it is moved BACK to the original car it must be RE-configured to that car again!!!!

The part number AND VCATS (/xxx) suffix need to match.

I have used a later part number (same number LNC1410 with later letter suffix ie. CB instead of CA or something like that???) BUT the /xxx NEEDS to match!!!!!!

If the original is LNC1410CB/103 then the /103 NEEDS TO MATCH!!!!!!!!!!!!!!!!!
and THEN the immobilization will need to be performed.

A better way to diagnose the fault would be to READ ALL THE MODULES to see if another one has faults that are affecting the ECM.
The INSTPK, Gear Selector Illumination Module, ECM, TCM and ABS are all on the CAN bus.

There are some MANUFACTURER SPECIFIC DTCs that your code reader might not detect????? Try a different reader to see if the results are the same????

bob gauff

 

Would a faulty ignition switch cause a restricted performance message? The lights on the car do not work and when I flick the key on the headlights come on then go off.

I have a Carsoft i930 and have read the engine, transmission, ABS and none show any codes. I will get my generic code reader and see if it finds anything.

If I cannot solve it the car will be sold for parts or parted out.

 

my 2001 has different plug ins from the 98/99, even the radio plug is diff